Fusible plug for automatic fire-extinguishers



(No Model.)

R. D. J NSON.- I v FUSIBLE PLUG FOR AUTOM FIRE EXTINGUISHBRS. No. 556,631. Patented Mar. 17,1896.

427 726? sea:

W M. W

UNITED STATES PATE T OFFICE;

ROY D. JOHNSON, OF CHICAGO, ILLINOIS.

FUSIB LE PLUG FOR AUTOMATIC FIRE-EXTINGUISHERS.

SPECIFICATION forming part of Letters Patent No. 556,631, dated March 17, 1896.

Application filed December26, 1894. Serial No. 533,019. (No model.)

To all whom it may concern.-

Be it known that I, ROY D. JOHNSON, a citizen of the United States, residing at Chicago, Cook county, State of Illinois, have invented certain new and useful Improvements in Fusible Plugs for Automatic Fire-Extinguishers, of which the following is a specification.

My invention relates to outlets for fire-extinguishers in which are provided means whereby the extinguishing medium is released automatically by the heat of a fire which may be started, and also means whereby said medium may be released at will by turning a stop-cock.

The automatic releasing device comprises a cap having a restricted passage and an intermediate enlarged tapered cavity containing a correspondingly-tapered plug of material, preferably metal, which is capable of being reduced to a melted state at a certain predetermined temperature. This form of plug, which is inserted in the cavity forming part of the escape-opening, is better adapted to withstand the great internal pressure on the escape-opening, and will effect a tighter closure by reason of said pressure. The plug may be cup-shaped or concaved, so that while maintaining the increased contact with the sides of the cavity the amount of metal necessary to be melted to permit the escape of the extinguishing medium is greatly reduced, and the readiness with which the device responds to the heat of an incipient fire correspondingly increased.

The means for releasing the extinguishing medium at will comprises a turning plug intercepting the same escape-passage as is blocked by the plug and having two bores, one

of which is a diametrical bore permitting the passage of the contents to the fusible plug, while the other is an inclined bore for diverting said contents to a lateral opening, which may be provided with a base or other conductor for directing the contents at will.

My invention will be understood upon reference to the accompanying drawing, which is an axial section through a controlling-outlet for receivers.

1 represents a cap of a receiver for a fire-extin guishin g medium under pressure. This cap is provided with an escape-passage 2 which terminates in a plug-chamber 3, in which a plug 4 of fusible metal is inserted by pouring it in while in a melted state. This plug-chamber, which gives shape to the filling inserted therein, is made larger at its inner portion and tapered toward its outer portion, so that pressure applied upon it is not only strongly resisted and any possibility of its being forced out obviated, but pressure upon it wedges it more intimately into contact with the walls of the chamber Sand insures a tighter closure to the receiver against the escape of gas.

The plug 4 may if desired have the further feature of a cavity 5, as shown, which will admit the pressure somewhat toward the interior of it, and by reason of lateral pressure the substance of the plug will be forced into better contact with the surface of the plug chamber and more effectually prevent escape of the gas or other fire-extinguishing medium which may be contained in the device to which the cap is applied.

I11 practice the cap 1 is attached to a nozzle G, in which the passage 2 is likewise formed, a threaded socket 7 on the cap and a nipple 8 on the nozzle being provided for attaching the parts together. A controllingbarrel 0, having a diametrical bore 10 and an inclined bore 11, is made to intersect the passage 2 and thus form a two-way controlling" cock, which may be turned to bring the upper end of a passage 2 into communication either with the outlet closed by the fusible plug or with a lateral outlet 12, to whichis applied a hose 13 for directing the extinguishing medium at will. From the construction it will be evident that a further turning of the cock will close both outlets and permit removal of the automatic releasing-cap or replacing or adjustment of same, as may be necessary.

The hand-controlled outlet may be used to direct gas in case of emergency or used to permit the charging or recharging of the receiver or tank, or charging and recharging could be effected through the straight passage by detaching the cap containing the fusible plug.

To provide for formation of cavity 5, as shown, it may be desirable to open up the space above the plug 4 by providing an enlarged socket 7 in the cap 1 and correspondingly increasing the size of the nipple 8 on the nozzle 6 This does not, however, interfere with the restricted straight passage 2 from the receiver. The object and an advantage of this restricted straight passage is that while permitting the communication of the full pressure of the receiver during inactivity of the device it acts as a controller during escape of the contents, so as to permit gradual outflow and prevent clogging of the small opening which would first be formed by the full pressure through the fused metal and which might be obstructed by the buckling or compression of the remaining partly-melted metal.

The use of fire-extinguishers arranged so that the extinguishing medium will be automatically released by the heat of a conflagration melting a fusible closure is too well understood to require explanation here. I desire it understood, however, that my invention is capable of being applied to all such devices, and I desire it further understood that while I have described the part 4 as a cap said part may be in the form of a cap or plug or may be a portion of the outlet of the holder or distributer of the extinguishing medium.

Having thus described my invention, the

following is what I claim as new therein and desire to secure by Letters Patent:

1. For use in connection with receptacles for containing a high-pressure fireextinguishing medium, a combined two-way cock and fusible valve for controlling the outlet from the receptacle, provided with a restricted straight passage and an inclined passage, a cock having a straight bore and inclined bore adapted to register with the passages in the cap; said device having also an enlarged intermediate tapered cavity containing a fusible plug to which pressure is communicated through the straight bore, substantially as and for the purpose set forth.

2. In a fusible closure for automatic fireextinguishers, the combination of a cap for attachment to the part to be controlled, having a tapered cavity and a correspondinglytapered cup-shaped plug of fusible material fitting in said cavity and having its open side presented toward the pressure, as and for the purpose set forth.

ROY D. JOHNSON.

Witnesses:

'loM BROWN, F. S. SAVAGE. 

